Octopi

Inclusions of Other Grown Analogues. A variety of crown analogues and hybrid modifications (24—28) with other topological features (lariat ethers (31,32), octopus molecules (33), spherands (eg, (12) (34), torands (35)) including chiral derivatives (36) have been prepared and demonstrated to show particular inclusion properties such as chiroselective inclusion (Fig. 4) (37) or formation of extremely stable complexes (K ">(LR) for (12)... 

Both of these structures are open-chained compounds corresponding to crown ethers in function if not exactly in structure (see Chap. 7). They have repeating ethyleneoxy side-chains generally terminated in a methyl group. Montanari and co-workers introduced the polypodes 22 as phase transfer catalysts . These compounds were based on the triazine nucleus as illustrated below. The first octopus molecule (23) was prepared by Vogtle and Weber and is shown below. The implication of the name is that the compound is multiarmed and not specifically that it has eight such side-chains. Related molecules have recently been prepared by Hyatt and the name octopus adopted. For further information on this group of compounds and for examples of structures, refer to the discussion and tables in Chap. 7. 

In specific applications to phase transfer catalysis, Knbchel and his coworkers compared crown ethers, aminopolyethers, cryptands, octopus molecules ( krakenmole-kiile , see below) and open-chained polyether compounds. They determined yields per unit time for reactions such as that between potassium acetate and benzyl chloride in acetonitrile solution. As expected, the open-chained polyethers were inferior to their cyclic counterparts, although a surprising finding was that certain aminopolyethers were superior to the corresponding crowns. 

In 1974, Vogtle and Weber disclosed the preparation of a class of molecules which they reported showed remarkable phenomenological parallelisms to the mode of food capture by an octopus using its suction pads . Such molecules have also been referred to as hexa-hosts (see below). 

The work of Hyatt on cyclotriveratrylene—derived octopus molecules contrasts with this. Of course, these species have the advantage of ligand directionality absent in the benzene-derived octopus molecules. Except for the shortest-armed of the species (i.e., n = 1), all of the complexing agents (i.e., n = 2—4) were capable of complexing alkali metal cations. Synthesis of these species was accomplished as indicated below in Eq. (7.7). These variations of the original octopus molecules were also shown to catalyze the reaction between benzyl chloride and potassium acetate in acetonitrile solution and to effect the Wittig reaction between benzaldehyde and benzyltriphenylphos-phonium chloride. 

In Mollusca, bioluminescence occurs in a great variety of organisms having distinctly different appearances, such as the classes Gastropoda (limpets, snails and sea hares), Bivalvia (clams), and Cephalopoda (squids and octopuses). All luminous molluscs currently known are marine organisms, except the New Zealand fresh water limpet Latia neritoides and the Malaysian land snail Quantula (Dyakia) striata. No information is yet available on the biochemical aspects of the Quantula luminescence. 

Only three kinds of octopus have been confirmed to be biolu-minescent Japetella, Eledonella, and Stauroteuthis syrtensis (Johnsen et al., 1999). No information is available concerning the biochemistry of their luminescence. 

Copper is essential in animal metabolism. In some animals, such as the octopus and certain arthropods, it transports oxygen through the blood, a role performed by iron in mammals. As a result, the blood of these animals is green rather than red. In mammals, copper-bearing enzymes are necessary for healthy nerves and connective tissue. 

Nonetheless, it was a fairly short step from octopus compounds to dendrimers, and the step was taken by Vogtle in the late 1970s when he attempted to use a cascade reaction to prepare a molecule of the dendrimer type that would now be considered a dendron rather than a fully developed dendrimer. It began with the addition of acrylonitrile to an anfine, followed by reduction of the nitrile to amine. This was followed by a further reaction with acrylonitrile, and the process was repeated several times to yield highly branched macromolecules. There were initially problems with the reduction step but these were overcome, and the preparation of these poly(propylene imine) dendrimers was later commercialized. 

The cephalopods often secrete venom from their posterior salivary glands and hence secretion of venom probably forms part of the process of digestion. Cephalopods include species, such as octopi, capable of injecting various venoms including simple amines such as tetramine. On the other hand, maculotoxin isolated from the octopus H. maculosa was eventually determined to be tetrodotoxin 24 ). 

Encyclopedia of magic and superstition alchemy, charms, dreams, omens, rituals, talismans, wishes. London Octopus Books, 1974. 5-253 p. ISBN 0-7064-0396-7... 

M. Dubber and T. K. Lindhorst, Trehalose-based octopus glycosides for the synthesis of carbohydrate-centered PAMAM dendrimers and thiourea-bridged glycoclusters, Org. Lett., 3 (2001) 4019 1022. 

St. Lawrence River 1989-90 sediment copper ranged from 4 to 148 mg/kg DW Octopus, Eledone cirrhosa-, English Channel October, 1987 ... 

Figure 7 of reference 11 compares similarities between Limulus and Octopus hemocyanins by illustrating the overlap of 30 amino acids about the CuB region. The authors find that all residues within 5.0 A of the Cu-Cu midpoint are conserved between arthropodan and molluscan hemocyanins and occupy analogous positions except for one (see the following paragraph). The three histidines about CuB overlap almost exactly in orientation and are less than 1 A apart. The histidines... 

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